Debt

Issuance and Sale of 6.375% Senior Notes Due 2022

On March 9, 2012, the Company issued $600 million aggregate principal amount of its 6.375% Senior Notes due 2022 (2022 Notes) for net proceeds of $589.5 million. Interest is payable in arrears semi-annually in March and September of each year, beginning September 2012. The 2022 Notes are senior unsecured obligations of the Company, which rank effectively junior to all of the Company's existing and any future secured debt, to the extent of the value of the collateral securing that debt, equally in right of payment with the Company's 10.25% Senior Notes due 2014 (2014 Notes) and 6.75% Senior Notes due 2020 (2020 Notes), and senior in right of payment to all of the Company's existing and any future subordinated debt.

On and after March 15, 2017, the Company may redeem all or, from time to time, a part of the 2022 Notes upon not less than 30 nor more than 60 days’ notice, at the following redemption prices (expressed as a percentage of principal amount of notes to be redeemed), plus accrued and unpaid interest, if any, to the applicable redemption date (subject to the right of holders of record on the relevant record date to receive interest due on the relevant interest payment date), if redeemed during the 12-month period beginning on March 15 of the years indicated below:



2017	103.188	%
2018	102.125	%
2019	101.063	%
2020 and thereafter	100.000	%

In addition, before March 15, 2015, the Company may, at its option, on any one or more occasions redeem up to 35% of the aggregate principal amount of the 2022 Notes with the net cash proceeds of certain equity offerings and if certain conditions are met as described in the indenture governing the 2022 Notes, at a redemption price of 106.375% of the principal amount thereof, plus accrued and unpaid interest, if any, to the redemption date. At any time prior to March 15, 2017, the Company may also redeem all or part of the 2022 Notes at a redemption price equal to 100% of the principal amount of the Notes redeemed plus a “make-whole” premium described in the indenture, plus accrued and unpaid interest, if any, to the redemption date.

Pursuant to the terms of the credit facility, the issuance of the 2022 Notes automatically reduced the borrowing base of the credit facility by 25 cents per dollar of the 2022 Notes issued.

Tender Offer and Redemption of Notes

Concurrently with the offering of the 2022 Notes, the Company conducted a cash tender offer for up to $150.0 million aggregate principal amount of the Company's 2014 Notes, which expired on April 2, 2012. Pursuant to the terms of the credit facility, the repurchase of $150.0 million of 2014 Notes in the tender offer increased the borrowing base of the credit facility by 25 cents per dollar of the 2014 Notes repurchased.

Upon the closing of the offering of the 2022 Notes, the Company issued a notice to redeem all $200 million aggregate principal amount of the Company's 2016 Notes at a total redemption price of approximately $215.5 million, including accrued and unpaid interest. The redemption of the 2016 Notes was completed on April 9, 2012. Pursuant to the terms of the credit facility, the redemption of subordinated notes does not affect the borrowing base of the credit facility.

For additional discussion of the tender offer and redemption, see Note 11 to the Condensed Financial Statements.

Senior Secured Revolving Credit Facility

As of March 31, 2012, the Company's credit facility had a borrowing base of $1,287.5 million after giving effect to adjustments related to the Company's issuance of its 2022 Notes and the repurchase of its 2014 Notes in the tender offer. At March 31, 2012, lender commitments under the facility were $1.2 billion. On April 13, 2012, the Company entered into a fourth amendment to its credit facility, which increased the borrowing base to $1.4 billion. For additional discussion of the amendment, see Note 11 to the Condensed Financial Statements.

Borrowings under the credit facility bear interest at either (i) LIBOR plus a margin between 1.50% and 2.50% or (ii) the prime rate plus a margin between 0.50% and 1.50%, in each case, based on the amount utilized. The annual commitment fee on the unused portion of the credit facility ranges between 0.35% and 0.50% based on the amount utilized.

As of March 31, 2012, there were $23.2 million in outstanding letters of credit and no outstanding borrowings under the facility, leaving $1,176.8 million in borrowing capacity available under the credit facility. As of December 31, 2011, there were $531.5 million in outstanding borrowings under the credit facility. The maximum amount available under the credit facility is subject to semi-annual redeterminations of the borrowing base in April and October of each year, based on the value of the Company's proved oil and natural gas reserves, in accordance with the lenders' customary procedures and practices. The Company and the lenders each have a right to one additional redetermination each year.